1. Field of the Invention
The present invention relates to an outboard motor and, more particularly, to an outboard motor having an improved layout or structure of electrical equipments or parts of an engine thereof.
2. Prior Art
In general, an engine mounted to an outboard motor has a structure in which a crankshaft is vertically perpendicularly extends, in a usable state such as mounted to a hull, for example, and which employs an engine layout in which intake system parts are disposed on one side surface of the engine and exhaust (system) parts are disposed on the other side surface of the engine. The exhaust system parts includes an exhaust cover for closing an exhaust manifold or an exhaust passage projecting sideways of the engine, and such an exhaust system projecting portion constitutes a portion of the engine having the maximum width in the engine lateral direction.
Further, this projecting portion is extended in a vertical direction at substantially central portion of the side surface of the engine, and an electrical equipment box, in which a control (system) electrical equipment is accommodated, is disposed in an engine side surface space in front of the projecting portion.
Prior art provides a structure in which electric equipment comprising an ignition coil, a rectifier and a regulator is disposed in the above-described space and a structure in which the electrical equipment is disposed to the engine exhaust projecting portion itself, such as disclosed in Japanese Patent Laid-open Publication No.7-77140, Japanese Patent Laid-open Publication No.8-100671, Japanese Patent Laid-open Publication No.10-47221, Japanese Patent Laid-open Publication No.10-157693.
Meanwhile, a four-stroke-cycle engine mounted in the outboard motor has an engine temperature higher than that of a two-stroke-cycle engine. Therefore, in order to protect the electrical equipment from being suffered from the harmful heat of the engine, prior art also provides an example in which the electrical equipment is disposed in a lower portion of a flywheel to cool the electrical equipment by a wind generated by the flywheel, such as disclosed in Japanese Patent Laid-open Publication No.8-100645 and also provides an example in which the electrical equipment is mounted in a lid member of a cooling water passage provided in the exhaust passage in the projecting portion, such as disclosed in the Japanese Patent Laid-open Publication No.8-100671.
However, if the electrical equipment is disposed in the projecting portion of the exhaust system parts, the lateral width of the engine is further increased, and a cover for covering the engine is hence increased in size, which is disadvantageous for reducing the outboard motor both in size and weight.
On the other hand, if an ignition coil is disposed in the engine side surface space forward of the projection, a high-tension cord, which connects the ignition coil and an ignition plug disposed in an engine side surface space rearward of the projecting portion, straddles the projecting portion, which elongates the high-tension cord, and nose is prone to be generated.
Furthermore, it is necessary to provide a clearance between the projecting portion and the high-tension cord to prevent them from coming into contact with each other and the lateral width of the engine is adversely increased.
Further, when the ignition coil is disposed near the electrical equipment box in which the controlling electrical equipment is accommodated, a noise resistance of the control system electrical equipment must be enhanced, which will increases a manufacturing cost.
On the other hand, in an arrangement in which the flywheel cools the electrical equipment, it is absolutely necessary to increase the flywheel in size, and since a place where the electrical equipment is disposed is limited, and the flexibility of layout will be deteriorated.
The present invention has been accomplished in view of the above circumstances, and it is an object of the invention to provide an outboard motor having an improved structure of an electrical equipment arrangement in consideration of the compact size, reduction of noise and effective cooling ability.
This and other objects can be achieved according to the present invention by providing an outboard motor comprising:
an engine holder;
an engine disposed above the engine holder in a mounted usable state of the outboard motor;
an oil pan disposed below the engine holder; and
an engine cover covering the engine holder, the engine and the oil pan so as to define a space between the engine and the engine cover,
said engine comprising:
a crankcase in which a crankshaft extends vertically perpendicularly;
a cylinder block disposed rear side of the crankcase;
a cylinder head disposed rear side of the cylinder block;
an intake unit disposed to one surface side of the engine;
an exhaust unit disposed to another one surface side thereof, said exhaust system part being arranged so as to project outward from the another one surface side of the engine as an exhaust projection portion; and
an electrical equipment part,
wherein the space between the engine and the engine cover includes a space portion defined by the cylinder head, the exhaust projection portion and the engine cover and the electrical equipment part is disposed in the space portion.
In a preferred embodiment, an ignition plug is disposed to the cylinder head so as to define the space portion between the ignition plug and the exhaust projection portion between which ignition coil means is arranged. The ignition coil means is disposed in a vertical direction, the ignition plug includes a plug cap which is connected to the ignition coil means through a high-tension cord so that a connected portion between the ignition coil and the high-tension cord and a connected portion between the plug cap and the high-tension cord are disposed in a rear and obliquely downward direction.
A boss or bosses for mounting the electrical equipment part are integrally formed to the cylinder head, and a cooling water jacket is formed to the cylinder head in the vicinity of the boss.
The engine cover includes upper and lower cover sections in the vertical usable state of the outboard motor and the electrical equipment part including an element generating a heat, the electrical equipment element generating the heat being located below a dividing portion of the engine cover.
As explained above, according to the structure for mounting electrical equipment of the outboard motor of the present invention, the an intake system part is disposed on one side surface of an engine, comprising a cylinder head to which an ignition plug is mounted, a cylinder block and the like, and an exhaust system part is disposed on the other side surface of the engine, the exhaust system part project sideways of the engine to form the exhaust system projecting portion. The electrical equipment system part is disposed in the space between the ignition plug and the projecting portion on a side surface closer to the cylinder head. Therefore, the dead space can be utilized effectively, and the outboard motor can be made compact.
Further, since a plurality of ignition coils are disposed between the ignition plug and the projecting portion in the space formed on the side surface closer to the cylinder head, the noise is reduced, and the maintenance is facilitated.
Further, the plurality of ignition coils are disposed in a vertical direction, a plug cap of the ignition plug and the ignition coils are connected to each other through a high-tension cord, a connected portion between the ignition coil and the high-tension cord, and a connected portion between the plug cap and the high-tension cord are disposed in a rear and downward oblique direction. Therefore, attaching/detaching (mounting) performance of the ignition plug and the plug cap can be enhanced and the waterdrop is less prone to reach these connected portions.
Furthermore, since a boss for mounting the electrical equipment system part is integrally formed on the cylinder head, and a contact surface of the boss contacting with the electrical equipment system part is set as wide as possible, it is possible to prevent the electrical equipment part from being heated.
Further, since a cooling water jacket is disposed in the vicinity of the boss, it is possible to prevent the electrical equipment part from being heated.
Furthermore, a periphery of the engine is covered with an engine cover which can be divided into upper and lower two cover sections, some electrical equipment system parts such as regulator which generate great heat are disposed below a dividing surface of the engine cover and a gap between the electrical equipment system part and the engine cover is hence made small. Therefore, it is possible to reduce the number of parts.
Furthermore, since the electrical equipments, such as rectifier and regulator, which generate much heat, are arranged below the divided section of the engine cover so as to reduce a gap between it and the lower cover section, the possibility for a user to contact the electrical equipments can be prevented and, hence, no contact prevention cover or no display label will be needed.
The nature and further characteristic features of the present invention will be made clear from the following descriptions made with reference to the accompanying drawings.